KANSAS CITY, Mo. — Democrat Barack Obama turned out enormous crowds at his two stops in battleground Missouri on Saturday in what campaign aides said was a strategy of using his ability to command huge crowds as a way to build excitement heading into the final two weeks of the presidential campaign.

An estimated 100,000 people showed up in St. Louis Saturday morning to hear Obama speak at the Gateway Arch — the largest crowd ever to hear Obama in the United States.

Saturday evening, a crowd estimated at more than 75,000 thronged the Liberty Memorial near downtown Kansas City for an Obama rally.

Campaign aides said they hope to turn out comparable crowds in other battleground states. To get large crowds, the campaign is choosing outdoor venues with virtually unlimited capacity.